The purpose of this study was to examine the Social Network Size (SNS) and Physical Activity(PA) level of elderly Koreans and the association it has with Self-rated Health (SRH). A Cohort study was performed using The Korea Urban Rural Elderly cohort study(KURE) (2012 to 2015). The study included 3,515 subjects aged 65 years or older who responded to the social network size, physical activity, and self-rated health questionnaire. The result shows that the SNS was larger for elderly females (3.03±1.64) compared to elderly males (2.28±1.72). On the other hand, elderly males had higher PA levels (3630.86 ± 3578.39 MET min/week) than elderly females (2290.67 ± 2193.48 MET min/week) and were more positive in SRH (3.23±0.96) compared to elderly females (2.95±0.99). For elderly males, the SNS was associated with SRH as elderly males with a SNS of 7 had significantly higher SRH (Adjusted (Odds Ratio(OR)) 7.28, 95% Confidence Interval (CI): 1.35-39.20) compared to those with a SNS of 0. For elderly females, PA level was associated with SRH as elderly females with high PA levels had significantly higher SRH (Adjusted OR 2.57, 95% CI:1.55-4.26) compared to those with low PA levels. This study examined that the factors associated with SRH differed according to gender. Thus, further studies will be needed to promote the mental health of elderly Koreans.